I hear the hydration argument a lot. I've used Safale on 5 batches so far from extract kits where the yeast is sitting at room temp for months and I put it right into the aerated wort and get insane krausen in 24 hours.

With hydration I get insane krausen in 8 hours (and noticeable activity in 4). I prefer that.

bringing up my old thread. I am going to use this yeast again but now we're in winter and cold temps will be my problem. what's the lowest you want to go with this yeast? I know their website says 59 - 75F, but everyone said keep it around 64 to 65, so how does it do on the low temp end? thanks

04 is a beast of yeast and will do well 60 or above. Even in cold temps if you start higher than ambient, the heat generated from fermentation will carry you a bit. I would not go below the specified range.